(a) Field of the Invention
The present invention relates to an automatic transmission. More particularly, the present invention relates to a planetary gear set used in an automatic transmission.
(b) Description of the Related Art
A typical automatic transmission employs a planetary gear set. The planetary gear set includes a sun gear, pinion gears, a ring gear, and a carrier that carries the pinion gears.
While a vehicle is driven, the automatic transmission frequently changes gears, and power interaction between the sun, pinion, and ring gears also frequently changes. When the sun, pinion, and ring gears or an arrangement thereof is not precisely designed, vibration or noise may be increased during shifting of the gears.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.